Variable view arthroscope

ABSTRACT

A variable-view arthroscope or like instrument (endoscope, etc.) includes an elongated housing tube extending from an outer control end to an inner image input end that is closed by an input lens; the input lens preferably is a diverging lens. In the form shown FIGS. 6A-6C, the input lens has a concave inner surface and a concave outer surfaces. A lighting apparatus illuminates a surgical working area beyond the image end of the housing tube; the illumination may be projected outwardly through the input lens. A movable mirror intercepts light reflected from the surgical working area to produce a working image that is reflected to a fixed mirror that in turn reflects the working image to impinge upon the input end of a relay lens assembly. The working image is transmitted to a receptor, which is located near the outer (control) end of the housing tube. The relay lens applies the image to an image device, such as a conventional CCD unit, that transmits the image to a location exterior to the scope. A control member, shown as a control rod extending longitudinally within the housing tube, varies the position of the movable mirror between first and second limits, adding about 30° or more to the image available to a user of the instrument.

BACKGROUND OF THE INVENTION

Arthroscopes and other like optical instruments, such as endoscopes,have long been known in the field of surgery and in other fields. Inthis specification and in the appended claims the term "arthroscope"means and should be interpreted to include an endoscope or any otherlike optical instrument, whether used for surgery or otherwise. In thisapplication, the invention is described in connection with an instrumentemployed for surgery, as in human surgery.

Over the last fifteen or more years the nature of surgery has changedsubstantially, with minimally invasive surgery becoming a mainstay.Within the orthopedic community, in particular, arthroscopy and similartechniques have become the most common surgical procedures. Surgeryusing such techniques is less painful for the patient and, in mostinstances, can be performed more quickly and safely than with techniquesthat require greater invasion of the patient's body; anesthesia is alsoless complicated, the surgery can often be handled on an outpatientbasis, and the procedures are better from the standpoint of costeffectiveness. Patients return to normal life more quickly, and hospitalstays may be reduced in length or even eliminated. However, all of thesebenefits are available only if the minimally invasive surgery allows forbetter diagnostic capabilities, improved surgical techniques, andreduced iatrogenic damage. Similar benefits are available with other,non-surgical, instruments.

One problem in these minimally invasive techniques derives fromlimitations in the arthroscopes, endoscopes and other principal opticalinstruments employed. In particular, the rather limited field of viewafforded by even the best instruments commercially available in 1998 hasinhibited progress to at least some extent; available instruments andtechniques have not changed dramatically since 1985. A substantialimprovement in the field of view available to a person employing anarthroscope or like instrument for exploratory or repair procedures ismuch needed.

Several techniques for modification (widening) of the view offered byarthroscopic/endoscopic instruments have been proposed, but they havenot been especially successful. Generally, such proposals have requiredpacking a plurality of movable lenses or prisms into the input end ofthe instrument; the resulting problems of precision of construction,precision of relative movements, space requirements, opticaldistortions, and elimination of undesired "ambient" light have beensubstantial. This is not particularly surprising; interaction betweenthe prisms and lenses involved, along with light loss, exacerbates theproblem.

SUMMARY OF THE INVENTION

It is an object of this invention, therefore, to provide a new andimproved arthroscope that affords the user a broadened effective fieldof view with few or no added lenses or prisms, a minimum of movableparts, and no requirement for movement of the instrument to vary itsscope of view.

A related object of the invention is to afford a new and improvedarthroscope that is relatively simple and effective in construction,cost efficient and durable, yet has an improved and expanded field ofview.

Accordingly, the invention relates to a variable view arthroscopecomprising an elongated housing having an image input end spaced from anouter control end. An input lens, preferably a diverging type lens,closes (and usually seals) the image input end of the housing tube,which is bevelled at an angle of 30° to 60°. Lighting means are providedfor illuminating a working image area beyond the image input end of thehousing tube. An input lens, located in the input end of the housingtube, intercepts light reflected back from the working area. Thatreflected light constitutes a working image. The light image reflectedfrom the working area back through the input lens is directed to amovable mirror. The movable mirror may be rotatable or it may movelinearly. There is a control member, usually an elongated control rod,for varying the position of the movable mirror to any position or to aseries of fixed positions between a first limit position and a secondlimit position. A fixed mirror is positioned to intercept light from themovable mirror, re-directing that light toward a relay lens located nearthe fixed mirror position. A relay lens assembly directs the light imagefrom the fixed mirror through the length of the relay lens assembly toimpinge upon a focusing lens assembly. The focusing lens assemblyconsists of focusing and zoom lens and their controls and is preferablylocated in the control portion of the arthroscope.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a variable view arthroscope constructed inaccordance with a preferred embodiment of the invention;

FIG. 2 is an elevation view of the instrument of FIG. 1;

FIG. 3 is a plan view, on an enlarged scale, of the control portion ofthe arthroscope of FIGS. 1 and 2;

FIG. 4 is an elevation view, on an enlarged scale, of the controlportion of the instrument of FIGS. 1 and 2;

FIG. 5 is a detail view taken approximately as indicated by line 5--5 inFIG. 3;

FIG. 6A is a sectional, longitudinal elevation view, on an enlargedscale, of the image input end of the arthroscope of FIG. 1, adjusted fora maximum upward view;

FIG. 6B is a sectional elevation view, like FIG. 6A, of the image inputend of the arthroscope of FIG. 1, adjusted for an intermediate view;

FIG. 6C is a sectional elevation view, like FIGS. 6A and 6B, of theimage input end of the arthroscope of FIG. 1, adjusted for a maximumdownward view;

FIG. 6D is a sectional view taken approximately along line 6D--6D inFIG. 6A;

FIG. 7A is an elevation view, on an enlarged scale, of a slide memberused in the arthroscope of FIG. 1;

FIG. 7B is a plan view of the slide of FIG. 7A;

FIG. 7C is an end view of the slide of FIGS. 7A and 7B;

FIG. 8A is a plan view, on an enlarged scale, of a cam/axle member usedin the control end (FIG. 3) of the arthroscope of FIG. 1;

FIG. 8B is an end view of the cam/axle member of FIG. 8A;

FIG. 8C is an elevation view of the cam/axle member of FIG. 8A;

FIG. 9A is a plan view, on an enlarged scale, of two control knobs fromthe control end (FIG. 3) of the arthroscope of FIG. 1;

FIG. 9B is an end view of the control knobs of FIG. 9A;

FIG. 9C is a section view, taken approximately along line 9C--9C in FIG.9A, of the control knobs;

FIG. 10 is an elevation view, on an enlarged scale, of the lightingapparatus for the arthroscope of FIG. 1;

FIG. 11A is a longitudinal sectional elevation view, like FIG. 6A, ofthe input (viewing) end of an arthroscope comprising another embodimentof the invention, adjusted for a maximum upward view;

FIG. 11B is a sectional elevation view, like FIG. 11A, of the apparatusof FIG. 11A adjusted for an intermediate view; and

FIG. 11C is a sectional elevation view, like FIG. 11A, adjusted for amaximum downward view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

One preferred embodiment of the invention is illustrated as anarthroscope 30, shown in FIGS. 1-10.

As shown in FIGS. 1 and 2, arthroscope 30 includes an elongated housingtube 31, which has an image input end 32 and a control end 33. Housingtube 31, and more specifically its control end 33, may extend into theouter control portion 35 of arthroscope 30, shown in greater detail inFIGS. 3-5. As shown in FIGS. 1-4, the control portion 35, from which thecontrol end 33 of the housing tube 31 of arthroscope 30 projects, endswith a CCD attachment 36. The CCD attachment 36 is connected byappropriate means to an image screen (not shown) to be viewed by aperson using arthroscope 30. Because CCD attachment 36 may be ofconventional construction and does not constitute a part of the presentinvention, it has not been shown in detail.

As best shown in FIG. 2 and in the enlarged views of FIGS. 6A-6C, theimage input end 32 of housing tube 31 is of bevelled construction at itsextreme end; the bevel is usually between 30° and 60°. The outer end ofhousing tube 31, shown in enlargement in FIGS. 6A-6C, is closed by adiverging input lens 37 (plural lenses may be used). Input lens 37 isshown as having an outer concave surface 38 spaced from an inner concavesurface 39. Input lens 37 is preferably sealed into the tip of the inputend 32 of housing tube 31; a suitable seal material to mount lens 37 inplace in the end of housing tube 31 is any conventional sealing adhesiveapproved by the FDA for in vivo use. Input lens (or lenses) 37 may beformed of optical glass or any other suitable lens material. When asingle input lens is used, input lens 37 preferably has a rim matched asclosely as possible to the inside diameter of the housing tube 31 at itsimage input end 32 to assure a good seal between the housing tube andthe input lens. Similar expedients should be employed if plural inputlenses are utilized.

Arthroscope 30 includes, an outer control portion 35 and a light source41 that is connected to a lighting means or apparatus 42; see FIGS. 2and 4. The lighting assembly 42 includes one or more optic fiber bundles43; the fiber optic bundle (or bundles) extend to the input end of thearthroscope; see FIGS. 4 and 6D. The optic fiber bundles 43 have beenomitted in FIGS. 6A-6C (and in other Figures) because they may beconventional in construction. The lighting assembly 42 is utilized toilluminate a surgical working area (not indicated) beyond the imageinput end 32 of the housing tube; illumination of the surgical workingarea may be made through the input lens 37.

A control member, shown in FIG. 4 as a control rod 45, extendslongitudinally through the housing tube 31 from outer control portion 35to its input end 32. Rod 45 is used to vary the position of a slidablymovable mirror (See arrows A in FIGS. 6A-6C) having a base 46 and amirror surface 47 along the axis of rod 45. Mirror surface 47 is shownas planar in the drawings, but the movable mirror may be concave orother shapes. The mirror surface 47 is aligned with but spaced from theinner surface 39 of input lens 37. See FIGS. 6A-6C. The end of controlrod 45 is affixed to the movable mirror base 46, as best shown in theenlarged views of FIGS. 6A-6C. A suitable commercially availableadhesive may be used to join the end of rod 45 to the base 46 of themovable mirror; alternatively, soldering or brazing may be used ifdesired. The tip of control rod 45 may be polished and coated to afforda suitable movable mirror, eliminating the need for a separate part 46.

At the control end 35 of the arthroscope 30 the control rod 45 extendsinto and engages a slide 48. Slide 48 is driven linearly by means of twocontrol knobs 49 and 50, as described hereinafter in connection withFIGS. 9A-9C.

In the arthroscope 30, as best shown in FIGS. 6A-6C, the base 46 of themovable mirror 46, 47 slides linearly between a maximum upward viewposition (FIG. 6A), through an intermediate position (FIG. 6B), to amaximum downward view position (FIG. 6C). Of course, the movement of themovable mirror base 46 may be reversed, moving from its maximum downwardposition (FIG. 6C) toward its maximum upward position (FIG. 6A). Theimages that may be provided to a surgeon by the arthroscope 30 alloverlap. The maximum upward view of FIG. 6A, with movable mirror 46, 47advanced by control rod 45 to a position immediately adjacent input lens37, has an overlap of about fifty percent with the maximum downward view(FIG. 6C) afforded when the sliding mirror 46, 47 is fully retracted.

At the top of the input end of arthroscope 30, as seen in FIGS. 6A-6C,there is a fixed mirror comprising a base 51 and a reflective (mirror)surface 52. The fixed mirror surface 52 intercepts a light image fromthe movable mirror surface 47 and re-directs that light image to impingeupon the input end 53A of a relay lens assembly 53. Relay lens assembly53, FIGS. 6A-6C, may be of conventional construction having an outerstainless sleeve 54 for stability and directs the light toward areceptor, shown as a focusing lens assembly 55 (FIGS. 1, 2, 3 and 4).The focusing lens assembly 55 consists of focusing and zoom lens and isof conventional design. The focusing lens assembly 55 directs the lightimage in the customary manner, into the CCD attachment 36; see FIGS.1-4. A slide 48 is located in the control portion 35 of arthroscope 30;the slide, shown in FIGS. 7A-7C, comprises a main body 57 having anaxial relay lens opening 58; the relay lens opening 58 also extendsthrough an enlarged end 59 of the slide. A socket 61 also in slide 48,formed to align and attach control rod 45 to slide 48, is best shown inFIG. 7B. The control rod socket 61, in the illustrated embodiment, islocated directly below the axial opening 58 for the relay lens.

The cam portion 65 of cam/axle member 62 is positioned in a centraltransverse opening 63 in slide 48; see FIGS. 7A-7C for opening 63, FIGS.8A-8C for cam/axle member 62. Opening 63 is not quite circular incross-section; it is enlarged or "stretched" slightly, as is mostapparent in FIG. 7B. The cam/axle member 62 includes a large controlknob shaft attachment segment 64 of circular cross-section, cam segment65 contains a relay lens assembly slot 66, and a small control knobshaft attachment segment 67. This preferred construction is shown indetail in FIGS. 8A-8C. Two control knobs, shown in FIGS. 9A-9C, aremounted on the outer ends 64 and 67 of cam/axle member 62 (FIGS. 8A-8C).The control knobs include a right-hand control knob 49 that is fittedonto the large control wheel shaft attachment segment 64 of the cam/axlemember 62. The second or left-hand control knob 50 fits onto the smallercontrol knob shaft attachment segment 67 of cam/axle member 62. SeeFIGS. 8A-8C and 9A-9C.

The control knobs 49 and 50 and their shaft attachments 64 and 67,respectively, may be connected to each other by conventional means.Either of the control knobs 49 and 50 can be used to rotate cam 65within slide opening 63, thus causing slide 48 and the attached controlrod 45, to move linearly in relation to the rotational motion ofcam/axle 62.

The lighting assembly 42, illustrated in FIG. 2 and shown in greaterdetail in FIG. 10, may include a condenser lens 71 to focus light from asuitable source 41 onto one end 72 of the light bundles 43 that extendto the input end of the arthroscope 30. See FIG. 6D. Actually, there maybe two or more fiber optic light bundles 43; to supply light to theinput end of arthroscope 30. As previously noted, the lighting assemblymay be quite conventional in construction and hence has been describedonly generally.

Operation of the arthroscope 30, (FIGS. 1-10), can now be considered. Atthe outset, light from source 41 (FIG. 2) is focused upon the end 72 ofone or more fiber optic bundles 43, as by an appropriate lens 71 (FIG.10). As a consequence, a surgical working area just beyond the input end32 of the arthroscope 30 (FIGS. 1 and 2) is illuminated. In arthroscope30, illumination is effected through input lens 37 (FIGS. 6A-6C). Lightfrom bundle(s) 43, at least in part, reflects from the fixed mirror 51,52 onto the reflective surface 47 of the movable mirror, and through theinput lens 37 into the area to be illuminated.

A light image reflected from the surgical working area, after passingthrough input lens 37, impinges on the inclined reflective surface 47 ofthe movable mirror 46, 47. That light image is directed from the movablemirror surface 47 to impinge upon the reflective surface 52 of the fixedmirror 51. From the fixed mirror the light image is re-directed towardthe input end 53A of the relay lens assembly 53; see FIGS. 6A-6D. Therelay lens system 53 supplies the image to the CCD attachment 36,through focusing lens assembly 55, to be viewed by the surgeon or otherperson using the arthroscope 30.

If the person using arthroscope 30 is dissatisfied with the imageavailable through the CCD attachment 36, control knobs 49 and/or 50 maybe used to vary the image. That is, the control knobs, through cam/axlemember 62 (FIGS. 8A-8C), slide 48 (FIGS. 7A-7C), and rod 45 (FIGS.6A-6C) can be used to advance the movable mirror 46, 47 toward the inputlens 37 (see FIG. 6A), or to retract the movable mirror from the inputlens (see arrow A in FIGS. 6B and 6C) to a "lower" position. In this waythe image supplied to the surgeon or other person using the instrument30 can be and is varied to a substantial extent with no change in theposition of the instrument. In effect, the overall viewing range of theinstrument 30 is enhanced by at least thirty degrees with no need toreposition the instrument axially. Further correction of the image canbe afforded by appropriate software.

FIGS. 11A, 11B and 11C afford sectional elevation views of the input end132 of a modified instrument; thus, FIGS. 11A, 11B and 11C correspond toFIGS. 6A, 6B and 6C, respectively. In FIGS. 11A-11C, the referencenumerals and illustrated elements correspond to those employed in FIGS.6A-6C, except for those elements that have been modified. Thus, theinstrument input end 132 of a housing tube 131 is bevelled, aspreviously described, and is closed by an input lens 37. The input lens37 may have two concave lens surfaces, an outer surface 38 and an innersurface 39 as shown; other input lens structures may be used. A fixedmirror base 51 is mounted in the upper portion of housing tube 31,immediately adjacent input lens 37; the fixed mirror base 51 has areflective coating on its surface 52 that faces the input end 53A of arelay lens assembly 53.

In the modification shown in FIG. 11A, there is a pivotally movablemirror comprising a base 146 having a reflective surface 147. The mirrorbase 146 is pivotally mounted on a shaft 148 that extends transverselyof the instrument between the two sides 170 (only one shown) of agenerally U-shaped support member 171 positioned in the lower part ofhousing tube 131. The movable mirror base 146 is connected to the end ofa control rod 145, as by a pin 172; rod 145 is similar to rod 45. Thecontrol rod 145 can be moved linearly as indicated by arrow B in FIGS.11A, B and C.

The views of FIG. 11B and FIG. 11C are the same as FIG. 11A except thatFIG. 11B shows the pivotally movable mirror 146, 147 at an intermediateposition, for an intermediate image, and FIG. 11C shows the pivotallymovable mirror 146, 147 positioned for a maximum "downward" view. Itshould be understood that FIGS. 11A-11C are assumed to be verticallyoriented. They could equally well be horizontally oriented, as couldFIGS. 6A-6C, so that references to "upward" and "downward" could equallywell be modified to "right" and "left", or vice versa. Because thecontrol rod 145 acts as previously described for rod 45, and becauseonly the movable mirror has been changed, from linear movement torotational movement, it is believed to be unnecessary to provide anyfurther description, structural or operational, of the arrangement shownin FIGS. 11A-11C.

Several parts of instrument 30 can be changed from those illustratedwithout appreciable effect on overall operation of instrument 30. Forexample, input lens 37, the shape of the movable mirrors 46, 47 and 146,147 and the illustrated relay lens assembly 53 can be changed, as canthe lighting assembly 42, 43. It will be recognized that the control rod45 (or rod 145) may be modified; it constitutes a preferred mechanismfor operating the movable mirror but any desired alternative that willmove that mirror, whether linearly or along a pivotal or other requiredpath, can be used. The angle of the level of the outer end of housingtube 31 may be varied as desired; a level of 30° to 60° is preferred,but may depend on the primary use for instrument 30. It will berecognized that use of a CCD unit for a display is not essential. The"software" used for the display may vary appreciably. Any preferredtechnique to enable the instrument user to move the movable mirror overits operational range is acceptable.

I claim:
 1. A variable view arthroscope comprising:an elongated housingtube having an image input end spaced from an outer control end; aninput lens closing the image input end of the housing tube; a lightingapparatus for illuminating a working image area beyond the image inputend of the housing tube; a movable mirror intercepting light,constituting a working image, reflected from the working area throughthe input lens; a control member for varying the position of the movablemirror between a first limit position and a second limit position; afixed mirror positioned to intercept light from the movable mirror,re-directing that light toward a relay lens location within the housingtube near its input end; a relay lens assembly, having an input end nearthe fixed mirror position, for directing light from the fixed mirrorthrough the housing tube toward a receptor; and a focusing receptor,located adjacent to the control end of the housing tube.
 2. A variableview arthroscope, according to claim 1, in which the input lens is adiverging lens.
 3. A variable view arthroscope, according to claim 1 inwhich said input lens is an image-expanding lens.
 4. A variable viewarthroscope, according to claim 1, in which the image input end of thehousing tube is beveled at an angle of about 30° to about 60°; and theinput lens extends across the bevelled input end of the housing tube. 5.A variable view arthroscope, according to claim 1, in which the lightingapparatus radiates light through the input lens toward the working imagearea.
 6. A variable view arthroscope, according to claim 1, in which themovable mirror moves by sliding toward and away from the input lens tomodify the working image.
 7. A variable view arthroscope, according toclaim 6, in which the movable mirror has at least three positions, andfurther comprising:a mechanism, at the control end of the housing,establishing two of those positions at the first and second limitpositions for the movable mirror and at least one intermediate positionbetween the first and second positions.
 8. A variable view arthroscope,according to claim 1, in which the movable mirror is a concave mirror.9. A variable view arthroscope, according to claim 1, in which themovable mirror moves by rotating about an axis transverse to the inputend of the housing tube.
 10. A variable view arthroscope, according toclaim 9, in which the movable mirror has at least three positions, andfurther comprising:a mechanism, at the control end of the housing, forestablishing two of those positions at the first and second limitpositions for the movable mirror and at least one intermediate positionbetween the first and second positions.
 11. A variable view arthroscope,according to claim 1, in which the control member is an elongatedcontrol rod extending through the housing tube between the control endand the image input end of the housing tube, the arthroscope furthercomprising:a control mechanism, located at the control end of thehousing tube and connected to the control rod, for moving the movablemirror between its limit positions without change of the position of thearthroscope.
 12. A variable view arthroscope, according to claim 1, inwhich the relay lens is located in the image end of the housing tube,with an input surface adjacent to the fixed mirror.
 13. A variable viewarthroscope, according to claim 12, in which:the relay lens assemblycomprises an elongated optical guide, having an input end and an outputend, the relay lens assembly extending from the input image end of thehousing tube to the control end thereof; and a focusing lens, locatedadjacent the control end of the housing tube, for focusing an image fromthe output end of the optical guide onto a CCD device.
 14. A variableview arthroscope, according to claim 13, in which the focusing lensworks with an image-erecting prism.